Takes 1 month to process a standard Russian tourist visa (including letter of invitation, voucher, itinerary and visa stamp). Validity for tourist visa is 30 days. May be able to process quicker for a higher charge.

For a Russian business visa, the cost will be more. For that you will also need an AIDS test and the validity is 3 months, if approved.

Xanadu Travel in Itaewon is currently refusing to do Russian visas, apparently due to their complexity.

In addition, you will almost certainly need a confirmed ticket and confirmed accommodation in Russia. This may be in the form of a ferry ticket ex-Sokcho, a confirmed flight to Moscow, a hotel booking in Russia and similar.

I don't think Canadians get any exemptions from these rules, unless perhaps you were born in Russia or nearby CIS.

I was in Russia a few years ago.
Go to www.waytorussia.net to get your invitation ($30) to apply for a visa at the embassy in Central Seoul. The invitation is just a beaueaucartic formality left over from the Soviet days.
Go early to get in line before the travel agents with stacks of passports. I think it was about 70000won a couple years ago.